Explosive charge pistol

ABSTRACT

1. In an explosive charge pistol, an elongated casing having at least one opening and a booster inserted in one end thereof, A STAB-INITIATED DELAY DETONATOR MEANS FIXEDLY SUPPORTED IN SAID CASING AND LOCATED ADJACENT TO SAID BOOSTER IN ALIGNED RELATIONSHIP THEREWITH, A ROTATABLE SHUTTER MOUNTED IN SAID CASING BETWEEN SAID DELAY DETONATOR MEANS AND SAID BOOSTER, EXPLOSIVE LEADS DEFINING AN EXPLOSIVE PATH THROUGH SAID SHUTTER AND CARRIED BY SAID SHUTTER IN SUCH A MANNER THAT SAID LEADS ARE AXIALLY MISALIGNED WITH THE DELAY DETONATOR MEANS AND BOOSTER WHEN THE SHUTTER IS IN THE UNARMED POSITION THEREBY PROVIDING A SAFETY MEANS, A FIRST FLUID FILLED NORMALLY EXPANDED BELLOWS SUPPORTED IN THE OTHER END OF SAID CASING, A SECOND NORMALLY COLLAPSED BELLOWS SUPPORTED WITHIN SAID CASING, A PLATE ATTACHED TO SAID CASING BETWEEN SAID FIRST AND SECOND BELLOWS AND HAVING A VENT THEREIN FOR ESTABLISHING COMMUNICATION BETWEEN SAID FIRST AND SECOND BELLOWS, SPRING LOADED FIRING PIN MEANS CONNECTED TO SAID SECOND BELLOWS, DETENT MEANS TO RELEASE SAID FIRING PIN MEANS WHEN SAID SECOND BELLOWS IS IN AN EXPANDED POSITION, MEANS CONNECTED TO SAID SECOND BELLOWS AND SAID SHUTTER TO ROTATE SAID SHUTTER TO ALIGN SAID EXPLOSIVE LEADS WITH SAID DELAY DETONATOR MEANS AND SAID BOOSTER WHEN SAID SECOND BELLOWS HAS EXPANDED TO COMPLETE AN EXPLOSIVE TRAIN BETWEEN SAID DETONATOR MEANS AND SAID BOOSTER.

United States Patent Lewis Dec. 30, 1975 EXPLOSIVE CHARGE PISTOL [75] Inventor: Charles A. Lewis, Silver Spring, Md.

22 Filed: Apr. 12, 1963 21 Appl. No.: 272,809

2,961,955 11/1960 MacDonald 102/7 2,994,272 8/1961 Saunderson 102/76 3,030,886 4/1962 Junghans et a1. 102/79 3,084,627 4/1963 Holm 102/13 Primary ExaminerSamuel Feinberg Assistant Examiner-C. T. Jordan EXEMPLARY CLAIM 1. In an explosive charge pistol, an elongated casing having at least one opening and a booster inserted in one end thereof,

a stab-initiated delay detonator means fixedly supported in said casing and located adjacent to said booster in aligned relationship therewith,

a rotatable shutter mounted in said casing between said delay detonator means and said booster,

explosive leads defining an explosive path through said shutter and carried by said shutter in such a manner that said leads are axially misaligned with the delay detonator means and booster when the shutter is in the unarmed position thereby providing a safety means,

a first fluid filled normally expanded bellows supported in the other end of said casing,

a second normally collapsed bellows supported within said casing,

a plate attached to said casing between said first and second bellows and having a vent therein for establishing communication between said first and second bellows,

spring loaded firing pin means connected to said second bellows,

detent means to release said firing pin means when said second bellows is in an expanded position,

means connected to said second bellows and said shutter to rotate said shutter to align said explosive leads with said delay detonator means and said booster when said second bellows has expanded to complete an explosive train between said detonator means and said booster, releasable means locking said first bellows in said expanded position whereby when said pistol is submerged in water and said releasable means is released the hydrostatic pressure of the water acts on the first bellows forcing said fluid through the vent in said plate to expand said second bellows, the expansion of said second bellows cocking said spring loaded firing pin means and rotating said shutter to align said explosive leads with said delay detonator means and said booster, said firing pin means being released when said second bellows reaches the expanded position thereby striking said delay detonator means to initiate sequential firing of the delay detonator means, explosive leads and booster.

10 Claims, 5 Drawing Figures US, Pamm Dec. 30, 1975 Sheet 1 of2 3,929,55

VII l' liillzfiiil Illllllllllllll INVENTOR CHARLES A. LEVY/1S ATTY.

AGENT.

Dec. 30, 1975 Sheet 2 of2 3,929,55

INVENTOR. CHARLES A. LEWIS EXPLOSIVE CHARGE PISTOL The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

The present invention relates to an explosive charge pistol to be used with an underwater explosive charge to destroy underwater mines and more particularly to a mechanical-pyrotechnic pistol having a delay arming mechanism, a delay firing and detonation mechanism, a safety device and a sterilization means.

In the field of mine clearance (antimine) explosive depth charge pistols, it has been the general practice to employ electromechanical devices to detonate a main charge. Although such devices have served the purpose, they have not proved entirely satisfactory under all conditions of service for the reasons that the pistol was larger than necessary, relatively complicated, and the method of misaligning the sensitive element in the explosive train was undesirable and less safe than required. Since the device was electromechanical it required a rather large and expensive test set to check the timing, insulation and contact resistance.

The general purpose of this invention is to provide an explosive charge pistol which embraces all the advantages of similarly employed explosive charge pistols and possesses none of the aforedescribed disadvantages. To attain this, the present invention contemplates the use of a new pistol which will perform the same functions as prior explosive pistols but will be smaller, cheaper and more reliable after long term storage. The present device also provides a sterilizer to flood the pistol in case there is a failure to fire the pistol, and a safety device to prevent accidential or premature detonation of the main charge.

An object of the present invention is the provision of a new and improved explosive charge pistol having a delay arming mechanism, a delay firing and detonation device, a safety device and a sterilization means.

Another object is to provide a new and improved mechanical-pyrotechnic explosive charge pistol.

A further object is to provide a novel delay arming means comprising a fluid filled orifice connected double bellows.

Still another object is to provide a safety device comprising a rotatable shutter containing explosive leads that are initially misaligned with a detonator and booster when in the disarmed position to prevent accidental or premature firing.

Yet another object of the present invention is the provision of a sterilization means comprising metal electrodes which react with the sea water to dissolve one of the electrodes and thereby flood the pistol rendering the explosives incapable of firing.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings in which like reference numerals designate like parts throughout the figures thereof and wherein:

FIG. 1 is a cross-sectional view of a preferred embodiment of the explosive charge pistol inserted in a main charge;

FIG. 2 is a cross-sectional view of the explosive charge pistol before it is fired and in a disarmed position;

FIG. 3 is a cross-sectional view of the explosive charge pistol after it is fired;

FIG. 4 is a cross-sectional view of the sterilization device, and

FIG. 5 is a perspective view partially broken away of the spider and cylinder.

Referring now to the drawings, wherein like reference characters designate like or corresponding parts throughout the several views, there is shown in FIG. 1 a housing containing a main explosive charge 11. An inner casing 12 is inserted in the housing 10 and main charge 11 and connected to the housing 10 by the end plate 13 and bolts 14. O-ring 72 provides a watertight seal between end plate 13 and casing 12. Latch 15 is connected to the upper bellows 17, the bellows being attached to plate 18 by suitable means. Seal 71 prevents sea water from entering chamber 56 when the latch is in a locked position. The upper bellows 17 contains silicon fluid which flows through orifice into lower bellows 19 when the upper bellows is subjected to the hydrostatic pressure of the sea water. Lower bellows 19 is connected to plate 18 by suitable means as by soldering the parts together and a rod 21 is inserted through both bellows and an opening 70 in plate 18. Bolts 54 secure plate 18 to the casing 12 and O-ring 52 provides a watertight seal between the chamber 56 and chamber 65. Orifice 20 acts as a vent for the silicon fluid from upper bellows 17 to lower bellows 19. Rod 21 is also inserted through hole 22 in spider 53 and is connected to a plate 28 by pin 29 and to striker 31 by pin 32. Groove 23 in rod 21 permits the rod to move within the striker in opening 66. Spider 53 is connected by pin 27 to cylinder 41. As the spider 53 moves axially downward as shown in FIGS. 2, 3 and 5, cylinder 41 is rotated by pin 27 which slides in the helical groove 55 in cylinder 41. Shutter 46 is connected to cylinder 41 by means of pin 42. The shutter 46 contains two explosive leads 43 which are not aligned with the detonator 36 in the unarmed position thereby providing a safety device to prevent accidental or premature firing. Charge container 33 contains two primers 34, two pyrotechnic delays 35 and two detonators 36. The dual firing lines of explosive charges insure detonation of the booster and main charge in case one firing line fails to ignite. Cap 37 is secured to charge container 33 by means of screw 38. After the shutter 46 has been rotated, the holes 39 in the cap 37 align with the explosive leads 43. Balls located in apertures 24 in charge container 33 initially prevent striker 31 from detonating the primers 34. After the spider 53 is moved downward by the expansion of lower bellows 19, holes 26 in the spider will align with apertures 24 allowing the balls 25 to move into holes 26 thereby releasing the striker from its locked position. The four legs of spider 53 slide in and are prevented from rotating by four slots 73 in flange 44 of charge container 33 which is secured to the casing 12 by means of bolts 45. Spring serves as a bias between striker 31 and plate 28, which is pin connected to rod 21. An adapter 47 is inserted in the other end of the pistol and held in place by snap ring 48. A booster 49 is then inserted within the adapter and held in place by snap ring 50. Vents allow the explosive gases to vent into chamber 65 in the event of accidental or premature firing in the disarmed position.

In FIG. 4, there is shown the details of the sterilizer. A gasket 59 is inserted in the mounting screw 57 and silver electrode 60 and magnesium electrode 61 are then placed in the gasket 59. The silver electrode 60 is coated with silver chloride 62 which acts as a depolarizer. The mounting screw 57 of the sterilizer is inserted in the casing 12 and the assembly is made watertight by O-ring 58. Passage 63 connects chamber 56 to chamber 65 by the opening 64 in the casing 12 after the thin wall of the magnesium electrode 61 of the sterilizer has been eroded and penetrated by the sea water in chamber 56. It should be understood that the sterilizer may be composed of any combination of metals that react with the sea water to allow penetration of the thin wall of the electrode in the desired time.

The explosive charge pistol operates in the following manner. The explosive charge pistol is dropped from a vehicle and at the same time an arming wire is removed from the latch 15 allowing it to rotate through 90 thereby permitting movement of upper bellows 17. Since the upper bellows 17 is no longer held in a locked position, sea water entering through opening 16 acts on upper bellows 17 thereby compressing it and forcing silicon fluid through orifice 20 into lower bellows 19 thereby expanding the lower bellows. As can be seen in FIGS. 3 and 5 as the lower bellows l9 expands, spider 53 moves axially downward thereby rotating cylinder 41 and shutter 46 by means of the pin 27 and helical groove 55 in cylinder 41. The explosive leads 43 are now aligned with the holes 39 in the cap 37 and the detonators 36 to provide a direct firing path to detonate booster 49. When spider 53 has moved sufficiently downward to allow holes 26 to align with apertures 24 in the charge container 33, balls 25 will be forced into the holes 26 thereby releasing the spring biased striker 31 and allowing it to detonate primers 34. Primers 34 ignite the pyrotechnic delays 35 which burn for a predetermined time interval. Detonators 36 are not ignited and the firing path continues through explosive leads 43 (now aligned with the detonators) which detonate the booster 49 which in turn detonates the main charge 11.

If there is a failure to fire the explosive charge pistol, the sterilizer will flood the pistol after a predetermined time. Sea water in chamber 56 reacts with the magnesium electrode 61 and the silver electrode 60 to dissolve the thin wall of the magnesium electrode thereby providing a path for the sea water through passage 63 and opening 64 into chamber 65 and thus flood the pistol. This action renders the pistol safe as the corrosive action of the salt water in time renders the explosives incapable of detonating.

It can be seen that an arming delay has been furnished by the controlled transfer of silicone fluid from the upper bellows to the lower bellows thus arming the pistol. A firing delay and delay detonation have been obtained from the pyrotechnic delays in the detonator structure. A safety device has been furnished by misaligning the explosive leads between the detonators and booster in the disarmed position. A sterilization means has been obtained by sea water penetrating the sterilizer thereby flooding and disarming the pistol.

Thus, an explosive charge pistol has been provided having a delay arming mechanism, a delay firing and detonation mechanism, a safety device and a sterilizatron means.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. In an explosive charge pistol, an elongated casing having at least one opening and a booster inserted in one end thereof,

a stab-initiated delay detonator means fixedly supported in said casing and located adjacent to said booster in aligned relationship therewith,

a rotatable shutter mounted in said casing between said delay detonator means and said booster,

explosive leads defining an explosive path through said shutter and carried by said shutter in such a manner that said leads are axially misaligned with the delay detonator means and booster when the shuttter is in the unarmed position thereby providing a safety means,

a first fluid filled normally expanded bellows supported in the other end of said casing,

a second normally collapsed bellows supported within said casing,

a plate attached to said casing between said first and second bellows and having a vent therein for establishing communication between said first and second bellows,

spring loaded firing pin means connected to said second bellows,

detent means to release said firing pin means when said second bellows is in an expanded position,

means connected to said second bellows and said shutter to rotate said shutter to align said explosive leads with said delay detonator means and said booster when said second bellows has expanded to complete an explosive train between said detonator means and said booster,

releasable means locking said first bellows in said expanded position whereby when said pistol is submerged in water and said releasable means is released the hydrostatic pressure of the water acts on the first bellows forcing said fluid through the vent in said plate to expand said second bellows, the expansion of said second bellows cocking said spring loaded firing pin means and rotating said shutter to align said explosive leads with said delay detonator means and said booster, said firing pin means being released when said second bellows reaches the expanded position thereby striking said delay detonator means to initiate sequential firing of the delay detonator means, explosive leads and booster.

2. An explosive charge pistol as recited in claim 1 including a housing containing a main charge, said casing being mounted within said main charge and said housing in such a manner so as to provide a passage between the casing and main charge.

3. An explosive charge pistol as recited in claim 2 including normally closed sterilizermeans located in said casing in communication with the exterior thereof whereby when said pistol is armed and tired under water and there is a failure to detonate the pistol, water flowing through the sterilizer means into the passage between the casing and main charge and the opening in the pistol will flood the pistol and render the explosives incapable of detonating.

4. An explosive charge pistol as recited in claim 1 where the delay detonator means comprises a charge container containing two lines of charges, each line having a primer, pyrotechnic delay and a detonator thereby insuring detonation of the main charge in the event one line of charges fails to ignite.

5. An explosive charge pistol as recited in claim 1 where the means connecting the second bellows to the rotatable shutter is a spider attached to the second bellows having a pin slidable in a helical groove in a cylinder connected to the shutter, the cylinder being rotated as the spider is moved axially by the second bellows.

6. An explosive charge pistol as recited in claim 5 where the detent means that releases the firing pin means comprises a plurality of balls located in apertures in the charge container supporting said delay detonator means in said casing that align with holes in the spider only when said second bellows reaches the expanded position and are forced into these holes by the spring loaded firing pin means when the holes in the spider are so aligned with the apertures in said charge container.

7. An explosive charge pistol as recited in claim 3 where the sterilizer means comprises a mounting screw insertable in the wall of the casing,

a gasket housed within said mounting screw,

a silver electrode coated with silver chloride contained within said gasket,

and a thin walled magnesium electrode mounted in said silver electrode whereby when said Water reacts with the electrodes the thin magnesium wall is dissolved thereby permitting the water within the casing portion in which the first bellows is housed to flood the remaining portion of the casing by way of the passage between the main charge and the casing and through the opening in the casing.

8. An explosive charge pistol as recited in claim 2 including normally closed sterilizer means for flooding and disarming the pistol located in said casing in communication with the exterior thereof whereby when said pistol has been released under water and there is a failure to detonate the pistol, water flowing through the sterilizer means into the passage between the casing and main charge and through the opening in the pistol will flood the pistol to equalize the pressure on the first and second bellows thereby returning said second bellows to a half-collapsed condition, retracting the firing pin means and rotating the shutter to the unarmed position, to immediately disarm the pistol while the corrosive action of the salt water in time renders the explosives incapable of detonating.

9. An explosive charge pistol for use in a housing containing a main charge comprising an elongated casing having at least one opening therein, said casing being mounted within said main charge and said housing in such a manner so as to provide a passage between the casing and main charge,

a booster charge inserted in one end of said casing,

stab-initiated delay detonator means supported in said casing in aligned relationship with said booster,

movable means mounted in said casing between said delay detonator means and said booster charge, explosive leads carried by said movable means in such a manner that said leads are misaligned with the delay detonator means and booster when the 6 movable means is in the unarmed position thereby providing a safety means,

a first fluid-filled normally expanded bellows supported in the other end of said casing,

a second normally collapsed bellows supported within said casing,

a plate attached to said casing and positioned between said first and second bellows and having a vent therein for establishing communication between said first and second bellows,

spring loaded means for firing the delay detonator means connected to said second bellows,

means releasing said spring loaded firing means when said second bellows is in an expanded position,

means connected to said second bellows and said movable means for moving said movable means to align said explosive leads with said delay detonator means and said booster charge when said second bellows has expanded to thereby complete an explosive train between said detonator means and said booster charge,

releasable means locking said first bellows in said expanded position whereby when said pistol is submerged in water and said releasable means is released the hydrostatic pressure of the water acts on the first bellows forcing said fluid through the vent in said plate to expand said second bellows, the expansion of said second bellows cocking said spring loaded firing means and moving said movable means to complete said explosive train, said firing means being released when said second bellows reaches the expanded position for initiating sequential firing of the delay detonator means, explosive leads and the booster,

and normally closed sterilizer means located in said casing in communication with the exterior thereof for flooding and immediately disarming the pistol if there is a failure to detonate the pistol.

10. An explosive charge pistol as recited in claim 9 where the sterilizer means comprises a mounting screw insertable in the wall of the casing,

a gasket housed within said mounting screw,

a silver electrode coated with silver chloride contained within said gasket,

and a thin walled magnesium electrode mounted in said silver electrode whereby when said pistol has been released under water and there is a failure to detonate the pistol, said water reacts with the electrodes to dissolve the thin magnesium wall thereby permitting the water within the casing portion in which the first bellows is housed to flood the remaining portion of the casing by way of the passage between the main charge and the casing and through the opening in the casing, thereby to equalize the pressure on the first and second bellows and return said second bellows to a partiallycollapsed condition, retracting said firing means and moving the movable means to theunarmed position, to immediately disarm the pistol and in time to render the explosives incapable of detonating. 

1. In an explosive charge pistol, an elongated casing having at least one opening and a booster inserted in one end thereof, a stab-initiated delay detonator means fixedly supported in said casing and located adjacent to said booster in aligned relationship therewith, a rotatable shutter mounted in said casing between said delay detonator means and said booster, explosive leads defining an explosive path through said shutter and carried by said shutter in such a manner that said leads are axially misaligned with the delay detonator means and booster when the shuttter is in the unarmed position thereby providing a safety means, a first fluid filled normally expanded bellows supported in the other end of said casing, a second normally collapsed bellows supported within said casing, a plate attached to said casing between said first and second bellows and having a vent therein for establishing communication between said first and second bellows, spring loaded firing pin means connected to said second bellows, detent means to release said firing pin means when said second bellows is in an expanded position, means connected to said second bellows and said shutter to rotate said shutter to align said explosive leads with said delay detonator means and said booster when said second bellows has expanded to complete an explosive train between said detonator means and said booster, releasable means locking said first bellows in said expanded position whereby when said pistol is submerged in water and said releasable means is released the hydrostatic pressure of the water acts on the first bellows forcing said fluid through the vent in said plate to expand said second bellows, the expansion of said second bellows cocking said spring loaded firing pin means and rotating said shutter to align said explosive leads with said delay detonator means and said booster, said firing pin means being released when said second bellows reaches the expanded position thereby striking said delay detonator means to initiate sequential firing of the delay detonator means, explosive leads and booster.
 2. An explosive charge pistol as recited in claim 1 including a housing containing a main charge, said casing being mounted within said main charge and said housing in such a manner so as to provide a passage between the casing and main charge.
 3. An explosive charge pistol as recited in claim 2 including normally closed sterilizer means located in said casing in communication with the exterior thereof whereby when said pistol is armed and fired under water and there is a failure to detonate the pistol, water flowing through the sterilizer means into the passage between the casing and main charge and the opening in the pistol will flood the pistol and render the explosives incapable of detonating.
 4. An explosive charge pistol as recited in claim 1 where the delay detonator means comprises a charge container containing two lines of charges, each line having a primer, pyrotechnic delay and a detonator thereby insuring detonation of the main charge in the event one line of charges fails to ignite.
 5. An explosive charge pistol as recited in claim 1 where the means connecting the second bellows to the rotatable shutter is a spider attached to the second bellows having a pin slidable in a helical groove in a cylinder connected to the shutter, the cylinder being rotated as the spider is moved axially by the seCond bellows.
 6. An explosive charge pistol as recited in claim 5 where the detent means that releases the firing pin means comprises a plurality of balls located in apertures in the charge container supporting said delay detonator means in said casing that align with holes in the spider only when said second bellows reaches the expanded position and are forced into these holes by the spring loaded firing pin means when the holes in the spider are so aligned with the apertures in said charge container.
 7. An explosive charge pistol as recited in claim 3 where the sterilizer means comprises a mounting screw insertable in the wall of the casing, a gasket housed within said mounting screw, a silver electrode coated with silver chloride contained within said gasket, and a thin walled magnesium electrode mounted in said silver electrode whereby when said water reacts with the electrodes the thin magnesium wall is dissolved thereby permitting the water within the casing portion in which the first bellows is housed to flood the remaining portion of the casing by way of the passage between the main charge and the casing and through the opening in the casing.
 8. An explosive charge pistol as recited in claim 2 including normally closed sterilizer means for flooding and disarming the pistol located in said casing in communication with the exterior thereof whereby when said pistol has been released under water and there is a failure to detonate the pistol, water flowing through the sterilizer means into the passage between the casing and main charge and through the opening in the pistol will flood the pistol to equalize the pressure on the first and second bellows thereby returning said second bellows to a half-collapsed condition, retracting the firing pin means and rotating the shutter to the unarmed position, to immediately disarm the pistol while the corrosive action of the salt water in time renders the explosives incapable of detonating.
 9. An explosive charge pistol for use in a housing containing a main charge comprising an elongated casing having at least one opening therein, said casing being mounted within said main charge and said housing in such a manner so as to provide a passage between the casing and main charge, a booster charge inserted in one end of said casing, stab-initiated delay detonator means supported in said casing in aligned relationship with said booster, movable means mounted in said casing between said delay detonator means and said booster charge, explosive leads carried by said movable means in such a manner that said leads are misaligned with the delay detonator means and booster when the movable means is in the unarmed position thereby providing a safety means, a first fluid-filled normally expanded bellows supported in the other end of said casing, a second normally collapsed bellows supported within said casing, a plate attached to said casing and positioned between said first and second bellows and having a vent therein for establishing communication between said first and second bellows, spring loaded means for firing the delay detonator means connected to said second bellows, means releasing said spring loaded firing means when said second bellows is in an expanded position, means connected to said second bellows and said movable means for moving said movable means to align said explosive leads with said delay detonator means and said booster charge when said second bellows has expanded to thereby complete an explosive train between said detonator means and said booster charge, releasable means locking said first bellows in said expanded position whereby when said pistol is submerged in water and said releasable means is released the hydrostatic pressure of the water acts on the first bellows forcing said fluid through the vent in said plate to expand said second bellows, the expansion of said second bellows cocking said spring loaded firing means and moVing said movable means to complete said explosive train, said firing means being released when said second bellows reaches the expanded position for initiating sequential firing of the delay detonator means, explosive leads and the booster, and normally closed sterilizer means located in said casing in communication with the exterior thereof for flooding and immediately disarming the pistol if there is a failure to detonate the pistol.
 10. An explosive charge pistol as recited in claim 9 where the sterilizer means comprises a mounting screw insertable in the wall of the casing, a gasket housed within said mounting screw, a silver electrode coated with silver chloride contained within said gasket, and a thin walled magnesium electrode mounted in said silver electrode whereby when said pistol has been released under water and there is a failure to detonate the pistol, said water reacts with the electrodes to dissolve the thin magnesium wall thereby permitting the water within the casing portion in which the first bellows is housed to flood the remaining portion of the casing by way of the passage between the main charge and the casing and through the opening in the casing, thereby to equalize the pressure on the first and second bellows and return said second bellows to a partially-collapsed condition, retracting said firing means and moving the movable means to the unarmed position, to immediately disarm the pistol and in time to render the explosives incapable of detonating. 